Small amounts of agro-industrial byproducts in dairy ewes diets affects milk production traits and hematological parameters

Abstract

The aim of this study was to evaluate the effect of diets containing different dried byproducts on milk yield and composition, and blood hematological parameters of lactating ewes. Thirty-six Sarda dairy sheep at about 120 ± 10 days in milk and with an average pre-trial milk yield of 1720 ± 430 g/day were assigned to 4 experimental groups and fed four different diets: no byproduct (CON), dry tomato pomace (TP), dry grape marc (GM), and exhausted myrtle berries (EMB) supplementation. Feed intake, milk yield, milk composition and hematological parameters were affected by byproduct supplementation of the diet. In particular, ewes fed byproducts combined diets consumed less dry matter compared with the CON (1.88 vs. 1.79 in GM and 1.71 kg in EMB and TP groups) diet daily. The GM group exhibited a larger milk production (+200 g/day), as well as protein (+8.4 g/day) and fat (+5.5 g/day) milk contents compared to the CON group. The EMB group produced less milk compared to CON group (1050 vs. 1220 g/day). The addition of TP did not affect production performance in comparison to CON group. Any significant interaction among dietary treatment and sampling time was observed on daily feed intake, animal performances and milk coagulation properties. The analysis of the hematological profile showed values within the physiological range of the species for all groups, and were used to assess apparent good health conditions of ewes throughout the experiment. In conclusion, 100 g/day of GM in addition to the basal sheep diet allowed to improve milk yield and to maintain the health status of lactating animals.